A trader yells on the floor of the New York Stock Exchange on Feb. 1, 2013. / Spencer Platt, Getty Images

by Matt Krantz, USA TODAY

by Matt Krantz, USA TODAY

Betting history will repeat itself on Wall Street is making investors some serious money.

Past performance isn't supposed to be a predictor of future success, as it reads on countless brokerage disclaimers. But with some very notable exceptions, such as Apple, the best stocks this year so far are the same ones that beat the market last year.

Seven out of the 10 stocks that trounced the Standard & Poor's 500 last year by the widest margins are beating the market again this year, so far. Some winners have turned in impressive repeat performances, such as hard drive maker Seagate, which gained 86% in 2012 and is up 11% this year. That tops the S&P 500's 13.5% and 6.2% gains those same periods. Appliance maker Whirlpool is another dramatic example, having gained 114% in 2012. It's up 9.7% this year.

While it might be tempting to join the crowd and pile into last year's winners, there are some dangers to consider, including:

â?¢ Big exceptions to the rule. The biggest example of a 2012 stock darling that's not doing it again is Apple. The gadget maker blew past the S&P 500 last year, rocketing 31.4%. This year, it's down 17%, and analysts are racing to downgrade their price targets as competition heats up.

Similarly, wireless telecom Sprint Nextel soared 142% in 2012, but this year is up 0.8%.

â?¢ Repeat performances are often underwhelming. PulteGroup and Expedia were the first and fourth-best stocks of 2012, turning in impressive 189% and 112% gains, respectively. But while both are beating the market so far this year, their 8.5% and 5.5% gains aren't nearly the relative head-turners they were.

â?¢ Unexpected disappointments. Given that housing stocks were strong in 2012 and have been so far in 2013, investors might have assumed bank stocks would hitch a ride. Bank of America was one of the best stocks of 2012, more than doubling in value. But despite its solid 2012 and connection to housing, the stock is still down 1.2% this year. While most of the top 10 best stocks of 2012 are winning again in 2013, 50% of the top 100 best stocks are lagging the market, while 50% are beating it.

Chasing performance might be working this year, but it's often a recipe for disaster. Most of the big winners in 2011 didn't fare so well in 2012. More than three-quarters of the best stocks of 2011 wound up lagging the market in 2012.

"No one will run away from the pack; it doesn't work that way, at least not forever," Ablin says.